1 Table S1. Complete list of isolates used and accession numbers for their DNA sequences. 2 Asterisks on isolate names denote ex-type specimens. Genus Isolate name Isolate # BOLD Genbank Abbrev. Process ID Accessions Ach Achlya ambisexualis CBS 101.50 OOMYA1184-08 HQ708156, HQ643083 Ach Achlya ambisexualis CBS 383.79 OOMYA1185-08 HQ708155, HQ643082 Ach Achlya americana CBS 100.52 OOMYA1186-08 HQ708157, HQ643084 Ach Achlya aquatica* CBS 103.67 OOMYA1187-08 HQ708158, HQ643085 Ach Achlya bisexualis CBS 100.42 OOMYA1188-08 HQ708161, HQ643088 Ach Achlya bisexualis CBS 102.62 OOMYA1190-08 HQ708160, HQ643087 Ach Achlya bisexualis CBS 103.50 OOMYA1191-08 HQ708159, HQ643086 Ach Achlya caroliniana CBS 544.67 OOMYA1192-08 HQ708162, HQ643089 Ach Achlya colorata CBS 102.37 OOMYA1193-08 HQ708164, HQ643091 Ach Achlya colorata CBS 545.67 OOMYA1194-08 HQ708163, HQ643090 Ach Achlya conspicua CBS 103.37 OOMYA1195-08 HQ708165, HQ643092 Ach Achlya dubia CBS 101.38 OOMYA1196-08 HQ708167, HQ643094 Ach Achlya dubia CBS 546.67 OOMYA1197-08 HQ708166, HQ643093 Ach Achlya flagellata CBS 104.37 OOMYA1198-08 HQ708170, HQ643097 Ach Achlya flagellata CBS 107.35 OOMYA1199-08 HQ708169, HQ643096 Ach Achlya flagellata CBS 528.67 OOMYA1200-08 HQ708168, HQ643095 Ach Achlya glomerata CBS 105.50 OOMYA1201-08 HQ708171, HQ643098 Ach Achlya heterosexualis CBS 419.65 OOMYA1202-08 HQ708173, HQ643100 Ach Achlya heterosexualis CBS 420.65 OOMYA1203-08 HQ708172, HQ643099 Ach Achlya oligocantha CBS 101.44 OOMYA1204-08 HQ708174, HQ643101 Ach Achlya papillosa CBS 101.52 OOMYA1205-08 HQ708175, HQ643102 Ach Achlya racemosa CBS 103.38 OOMYA1206-08 HQ708178, HQ643105 Ach Achlya racemosa CBS 541.67 OOMYA1207-08 HQ708177, HQ643104 Ach Achlya racemosa CBS 578.67 OOMYA1208-08 HQ708176, HQ643103 Ach Achlya radiosa CBS 547.67 OOMYA1210-08 HQ708179, HQ643106 Ach Achlya recurva CBS 108.50 OOMYA1211-08 HQ708180, HQ643107 Ach Achlya sparrowii* CBS 102.49 OOMYA1213-08 HQ708181, HQ643108 Ach Achlya spinosa CBS 576.67 OOMYA1214-08 HQ708182, HQ643109 Alb Albugo candida AC2V OOMYA2013-10 HQ708184, HQ643111, HQ665049 Alb Albugo candida AC7A OOMYA2014-10 HQ708183, HQ643110, HQ665050 Aph Aphanomyces cladogamus BR 693 OOMYA1218-08 HQ708187, HQ643114 Aph Aphanomyces cladogamus CBS 690.79 OOMYA1217-08 HQ708185, HQ643112 Aph Aphanomyces cladogamus CBS 108.29 OOMYA1215-08 HQ708186, HQ643113, HQ665056 Aph Aphanomyces cochlioides CBS 477.71 OOMYA1216-08 HQ708188, HQ643115, HQ665241 Aph Aphanomyces euteiches BR 694 OOMYA1219-08 HQ708193, HQ643120 Aph Aphanomyces euteiches CBS 155.73 OOMYA1221-08 HQ708191, HQ643118 Aph Aphanomyces euteiches CBS 157.73 OOMYA1223-08 HQ708189, HQ643116 Aph Aphanomyces euteiches CBS 154.73 OOMYA1220-08 HQ708192, HQ643119, HQ665129 Aph Aphanomyces euteiches CBS 156.73 OOMYA1222-08 HQ708190, HQ643117, HQ665132 Aph Aphanomyces iridis* CBS 524.87 OOMYA1224-08 HQ708194, HQ643121, HQ665248 Aph Aphanomyces laevis CBS 478.71 OOMYA1226-08 HQ708195, HQ643122, HQ665242 Aph Aphanomyces sp. CBS 583.85 OOMYA1227-08 HQ708196, HQ643123, HQ665276 Apo Apodachlya brachynema CBS 184.82 OOMYA1229-08 HQ708197, HQ643124 Apo Apodachlya brachynema CBS 557.69 OOMYB040-08 HQ708198, HQ643125 Apo Apodachlya minima CBS 185.82 OOMYA1230-08 HQ708199, HQ643126 Bas Basidiophora entospora HV 119 DM011-10 HM033184, EF553487 Bas Basidiophora entospora HV 123 AY035513 Bre Brevilegnia gracilis* CBS 131.37 OOMYA1232-08 HQ708200, HQ643127, HQ665122 Bre Brevilegnia macrospora* CBS 132.37 OOMYA1908-08 HQ708201, HQ643128, HQ665124 Bre Brevilegnia unisperma var. delica CBS 143.52 OOMYA1233-08 HQ708202, HQ643129, HQ665125 Bre Brevilegnia variabilis CBS 110006 OOMYA1234-08 HQ708203, HQ643130, HQ665058 Eur Eurychasma dicksonii CCAP 4018/2 OOMYA2124-10 HQ708204, HQ665307 Eur Eurychasma dicksonii FI373 OOMYA2126-10 HQ643131 Hal Halophytophthora exoprolifera CBS 252.93 OOMYA1236-08 HQ708205, HQ643132, HQ665174 Hal Halophytophthora kandelii CBS 111.91 OOMYA006-07 HQ708207, HQ643134, HQ665065 Hal Halophytophthora kandelii CBS 113.91 OOMYA1237-08 HQ708206, HQ643133, HQ665079 Hal Halophytophthora tartarea* CBS 208.95 OOMYA043-07 HQ708208, HQ643135 Hya Hyaloperonospora nesliae HV 203 DM004-10 HM033185, AY198250, EU054892 Hya Hyaloperonospora sisymbrii-sophiae HV 276 DM007-10 HM033186, AY198253, EU054910 1 Lag Lagenidium caudatum CBS 584.85 OOMYA199-07 HQ708209, HQ643136, HQ665277 Lag Lagenidium giganteum CBS 580.84 OOMYA2112-10 HQ708210 Lag Lagenidium giganteum ATCC 36492 AY151183 Lep Leptolegnia caudata CBS 680.69 OOMYA213-07 HQ708211, HQ643137, HQ665287 Lep Leptolegnia sp. CBS 582.85 OOMYA1238-08 HQ708212, HQ643138, HQ665275 Peronospora aparines HV 97 DM001-10 HM033187, AY198300 Peronospora calotheca HV 81 DM002-10 HM033188, AY198298 Peronospora calotheca HV 83 AY035483 Peronospora conglomerata HV 26 DM003-10 HM033189, AY198246 Peronospora conglomerata HV 27 AY035489 Peronospora radii HV 22 DM005-10 HM033190, AY198296 Peronospora sherardiae HV 211 DM006-10 HM033191, AY198301 Peronospora valerianellae HV 41 DM008-10 HM033192, AY198293 Peronospora violae HV 34 DM009-10 HM033193, AY198240 Phy Phytophthora aff. citricola BR 1073 OOMYA1250-08 HQ708271, HQ643204 Phy Phytophthora aff. infestans P13660 PHYTO099-10 HQ261238, HQ261491 Phy Phytophthora aff. meadii CBS 235.30 OOMYA2081-10 HQ708214, HQ643140 Phy Phytophthora aff. meadii CBS 238.28 OOMYA2082-10 HQ708213, HQ643139 Phy Phytophthora aff. primulae P6817 PHYTO203-10 HQ261239, HQ261492 Phy Phytophthora aff. rosacearum P10678 PHYTO065-10 HQ261240, HQ261493 Phy Phytophthora alni CBS 117375 OOMYA2060-10 HQ708217, HQ643143 Phy Phytophthora alni CBS 117376 OOMYA2061-10 HQ708216, HQ643142 Phy Phytophthora alni IMI 392314 OOMYA2163-10 GU945463, GU993881 Phy Phytophthora alni P10564 PHYTO055-10 HQ261244, HQ261497 Phy Phytophthora alni P11193 PHYTO084-10 HQ261243, HQ261496 Phy Phytophthora alni P11318 PHYTO086-10 HQ261242, HQ261495 Phy Phytophthora alni P16202 PHYTO126-10 HQ261241, HQ261494 Phy Phytophthora alticola P16052 PHYTO120-10 HQ261245, HQ261498 Phy Phytophthora arecae CBS 305.62 OOMYA115-07 HQ708218, HQ643146, HQ665200 Phy Phytophthora austrocedrae P15132 PHYTO108-10 HQ261247, HQ261500 Phy Phytophthora austrocedrae P16040 PHYTO117-10 HQ261246, HQ261499 Phy Phytophthora avicenniae CBS 188.85 OOMYA036-07 HQ708219, HQ643147, HQ665146 Phy Phytophthora batemanensis* CBS 679.84 OOMYA212-07 HQ708220, HQ643148, HQ665286 Phy Phytophthora bisheria P11311 PHYTO085-10 HQ261249, HQ261502 Phy Phytophthora bisheria P7191 PHYTO217-10 HQ261248, HQ261501 Phy Phytophthora bisheria P10117 PHYTO013-10 HQ261250, HQ261503, EU080746 Phy Phytophthora boehmeriae P1257 PHYTO095-10 HQ261253, HQ261506 Phy Phytophthora boehmeriae P1378 PHYTO100-10 HQ261252, HQ261505 Phy Phytophthora boehmeriae p43 OOMYA2137-10 GU945465, GU993882 Phy Phytophthora boehmeriae P6950 PHYTO211-10 HQ261251, HQ261504, EU080166 Phy Phytophthora boehmeriae* CBS 291.29 OOMYA105-07 HQ708221, HQ643149, HQ665190 Phy Phytophthora botryosa P1044 PHYTO050-10 HQ261257, HQ261510 Phy Phytophthora botryosa P3425 PHYTO169-10 HQ261256, HQ261509 Phy Phytophthora botryosa p44 OOMYA2138-10 GU945466, GU993883 Phy Phytophthora botryosa P6944 PHYTO209-10 HQ261255, HQ261508 Phy Phytophthora botryosa P6945 PHYTO210-10 HQ261254, HQ261507, EU079939 Phy Phytophthora botryosa* CBS 581.69 OOMYA197-07 HQ708222, HQ643151 Phy Phytophthora brassicae CBS 112277 OOMYA2038-10 HQ708228, HQ643158 Phy Phytophthora brassicae CBS 180.87 OOMYA2074-10 HQ708224, HQ643154 Phy Phytophthora brassicae CBS 212.82 OOMYA2076-10 HQ708223, HQ643153 Phy Phytophthora brassicae CBS 782.97 OOMYA2115-10 HQ708226, HQ643156 Phy Phytophthora brassicae CBS 178.87 OOMYA034-07 HQ708225, HQ643155, HQ665144 Phy Phytophthora brassicae CBS 686.95 OOMYA2009-09 HQ708227, HQ643157, HQ665289 Phy Phytophthora brassicae P10155 PHYTO018-10 HQ261259, HQ261512, EU080794 Phy Phytophthora brassicae P3273 PHYTO164-10 HQ261258, HQ261511, EU079812 Phy Phytophthora cactorum BR 1067 OOMYA1249-08 HQ708240, HQ643170 Phy Phytophthora cactorum BR 194 OOMYA1242-08 HQ708239, HQ643169 Phy Phytophthora cactorum BR 672 OOMYA1245-08 HQ708237, HQ643167 Phy Phytophthora cactorum BR 673 OOMYA1246-08 HQ708236, HQ643166 Phy Phytophthora cactorum BR 675 OOMYA1248-08 HQ708235, HQ643165 Phy Phytophthora cactorum CBS 110121 OOMYA2019-10 HQ708238, HQ643168 Phy Phytophthora cactorum CBS 112275 OOMYA2037-10 HQ708234, HQ643164 Phy Phytophthora cactorum CBS 113344 OOMYA2039-10 HQ708233, HQ643163 Phy Phytophthora cactorum CBS 151.88 OOMYA2072-10 HQ708229, HQ643159 Phy Phytophthora cactorum CBS 231.30 OOMYA2078-10 HQ708231, HQ643161 Phy Phytophthora cactorum CBS 279.37 OOMYA2087-10 HQ708232, HQ643162 Phy Phytophthora cactorum CBS 294.29 OOMYA2089-10 HQ708230, HQ643160 2 Phy Phytophthora cactorum P10365 PHYTO043-10 HQ261260, HQ261513 Phy Phytophthora cactorum P0714 PHYTO008-10 HQ261261, HQ261514, EU080282 Phy Phytophthora cajani P3105 PHYTO157-10 HQ261262, HQ261515, EU080105 Phy Phytophthora cambivora CBS 111329 OOMYA2023-10 HQ708248, HQ643179 Phy Phytophthora cambivora CBS 114085 OOMYA2045-10 HQ708247, HQ643178 Phy Phytophthora cambivora CBS 114086 OOMYA2046-10 HQ708246, HQ643177 Phy Phytophthora cambivora CBS 114087 OOMYA2047-10 HQ708245, HQ643176 Phy Phytophthora cambivora CBS 114093 OOMYA2048-10 HQ708244, HQ643175 Phy Phytophthora cambivora CBS 114094 OOMYA2049-10 HQ708243, HQ643174 Phy Phytophthora cambivora CBS 114095 OOMYA2050-10 HQ708242, HQ643173 Phy Phytophthora cambivora CBS 356.78 OOMYA2100-10 HQ708241, HQ643172 Phy Phytophthora cambivora p64 OOMYA2142-10 GU945467, GU993885 Phy Phytophthora cambivora P0592 PHYTO006-10 HQ261263,